Commercial farming, including the growing and harvesting of algae, is of interest because the produced algae can have a variety of uses. For example, algae can produce bio-mass feed stocks for the production of bio-fuels such as: bio-diesel, bio-kerosene, bio-ethanol and the like.
One common way of commercially growing algae is to use an open system where the algae grow process is open to the elements. These open pond systems can best be described as a number of plastic or clay lined shallow dugouts, occupying hundreds of hectares of land area. Race track systems are one type of known open pond system.
The open pond algae grow operations do not allow control over the temperature and lighting of the algae, but instead rely on outside conditions, causing the growth rates of the algae to vary and making open pond type systems undesirable for some climates, including colder climates. Additionally, these operations can be vulnerable to contamination from other micro-organisms or other types of algae because of the openness to the environment. A further shortcoming of these open pond grow operations is that the depth of the ponds is typically kept relatively shallow to allow for sufficient penetration of the natural light.
Other approaches to growing algae include a clear, hanging bag and the clear plastic tube technologies. However, there are many innate problems associated with these approaches, primarily relating to durability and maintenance issues. Algae residue can build up inside the bags and block out sunlight, reducing the bags photometric grow efficiency; as a result the bags have to be regularly changed. The same fouling problems may occur in the clear plastic tubes. Additionally, the clear plastic tubes may degrade over time and have a limited life expectancy when exposed continuously to sunlight. This makes it necessary to replace the tubes every four or five years.
Additionally, many of these systems require an extensive and permanent installation to be constructed to provide the necessary infrastructure to support growth and harvesting operations, which can increase the land usage requirements.
Alternatives to the current state of the art for growing and harvesting algae are of interest as they may provide novel apparatus, methods and systems for growing and harvesting algae.